Django Rest Framework multipart renderer

A high-performance multipart (multipart/form-data) renderer for Django Rest Framework. This package allows you to return complex, nested data structures and binary files in a single multipart response.

Highlights

• Response renderer: Suitable as a DRF Response Renderer
• Smart Type Mapping: Automatically determines Content-Type for different Python objects.
• File Support: Handles file streams and automatically selects MIME types.
• JSON Integration: Serializes primitives and dictionaries as application/json parts.
• List Flattening: Supports multiple values for a single key (e.g., multiple tags or images).

Install

pip install drf-multipart-renderer

Usage

To use this renderer, add it to your renderer_classes in a DRF View or ViewSet.

Basic Example

from rest_framework.views import APIView
from rest_framework.response import Response
from drf_multipart_renderer import MultipartRenderer

class MyView(APIView):
    renderer_classes = [MultipartRenderer]

    def get(self, request):
        data = {
            "title": "Project Alpha",
            "metadata": {"version": 1.0, "active": True},
            "file": open("report.pdf", "rb"),
            "tags": ["python", "django"],
            "number": 33
        }
        
        return Response(data)

Data Type Mapping Logic

The MultipartRenderer automatically determines the Content-Type of each part in the response based on the Python type of the dictionary value.

Python Type	Target Content-Type	Handling Behavior
String (str)	text/plain	Encoded as standard UTF-8 text.
Primitives (int, float, bool)	application/json	Serialized as a JSON value.
Dictionary (dict)	application/json	Serialized as a JSON object.
File (has a callable read method)	guessed/type	Uses the file object's content_type if exists, else guesses type from filename; defaults to application/octet-stream.
Iterables (list, tuple)	Per-element type	Flattens the collection into multiple entries using the same key name.
None	application/json	Serialized as null.

Nested Collection Note

If an iterable (like a list) contains another collection (like a list of lists or a list of dicts), the nested collection is automatically serialized as a JSON string within that form entry.

Technical Details

The renderer generates a random boundary for every response.

It adheres to standard multipart formatting, using \r\n line endings as required by the HTTP specification.

Every component of the multipart payload (including field names, text values, JSON objects, and headers) is encoded using UTF-8 to ensure universal character compatibility.

TESTS

To run the test suite for this package, use the following command:

 DJANGO_SETTINGS_MODULE="src.tests.settings" python -m django test

License

MIT